Download Exam 1 Study Guide

HUMAN GENETICS
Exam 1 Study Guide
Week 1: Introduction — Being Human
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Provide the scientific name for the human species.
Explain what makes humans:
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animals
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mammals
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primates
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Identify where (geographically) our species originated.
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Identify the significance of the Human Genome Project, and be able to state the degree
of DNA sequence similarity between humans and chimpanzees.
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List the three basic types of cells that make up humans and describe their functions.
Describe the two hypotheses that attempt to explain how humans have migrated
around the world.
Explain the difference between autosomes and sex chromosomes, including how many
we get from each parent (assuming we’re all normal humans).
Week 2: Cell Division and Cancer
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Compare and contrast mitosis and meiosis.
Briefly explain what happens in each of the following stages of the cell cycle:
Interphase
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G1
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S
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G2
Mitosis
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Prophase
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Metaphase
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Anaphase
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Telophase
Cytokinesis
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Give examples of when cells would divide by mitosis (rather than by meiosis).
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Explain the difference between the terms diploid (2n) and haploid (n).
Explain why the cell cycle checkpoints are important.
Explain why sexually reproducing species use meiosis (rather than mitosis) for
reproduction.
Describe the process of meiosis, concentrating primarily on:
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HUMAN GENETICS
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Exam 1 Study Guide
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the major differences it has with mitosis
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the number of daughter cells produced
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the number of chromosomes in each daughter cell (diploid or haploid)
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whether or not the daughter cells are genetically identical or unique
Explain the two hallmarks of cancer.
Be able to define the following words:
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tumor
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metastasis
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benign
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malignant
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Be able to explain the effect(s) that mutations have on cancer. (What types of
mutations do we generally see in effect in cancer cells?)
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Explain the difference between a tumor-suppressor gene and a proto-oncogene, and
how mutations in each of these affects cell division.
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List the two high-risk breast cancer genes discussed in class. What makes these highrisk?
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Be able to explain why people from families with an inherited form of cancer are more
likely to develop cancer than someone from a family without an inherited cancer. (See
Jennifer and Sally in your notes.)
Week 3: Transmission Genetics
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Describe Gregor Mendel’s role in the history of genetics. Also, be able to give two
pieces of biographical information: where he lived (present-day Czech Republic in
Eastern Europe) and his time frame (mid-1800s).
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State and describe Mendel’s two laws:
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Law of Segregation
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Law of Independent Assortment
Explain what is meant by the term allele.
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How does an allele differ from a gene or trait? (It’s probably easiest to use an
example.)
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Explain the difference between a dominant allele and a recessive allele.
Explain the difference between the terms homozygous and heterozygous.
Explain the difference between the terms genotype and phenotype.
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Explain why, when you discuss genotypes for diploid organisms, you also have two
alleles (AA or Aa or aa).
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HUMAN GENETICS
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Exam 1 Study Guide
If you are told that B is the allele for brown eyes and b is the allele for blue eyes, you
should be able to fill in the following table:
genotype
phenotype
homozygous dominant
homozygous recessive
heterozygous
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Explain why* each diploid parent only gives one allele for a gene to its offspring. *What
process in the parent is responsible for this? Following fertilization, how many copies
does the offspring have?
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Describe Mendel’s Law of Segregation. (What does the term segregation mean? In
class, I told you to think about how the term has been used in U.S. history to describe
treatment of African-Americans in the South. How does that apply to alleles during
inheritance?)
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Be able to use Punnett squares to predict data from monohybrid crosses. For example,
if you are told to predict the possible outcomes from a Ff x ff cross, you should be able
to do the following:
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Figure out the possible gametes produced by each parent.
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Build a 2 x 2 grid.
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Place the gametes along the edge of the grid.
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Fill in the grid with the possible allele combinations.
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Report the predicted genotypic and phenotypic ratios from the cross.
Describe Mendel’s Law of Independent Assortment.
For a given parent’s genotype, be able to provide the different kinds of gametes that
this parent can produce.
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We did several of these in class; here are some more to practice.
1. BbNn
2. Tt
3. HHiiJJKk
4. EEMM
5. PpMM
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Answers to these are on the last page of this study guide.
Be able to calculate what the probability is that two independent events happen at the
same time.
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For example, if two parents have a 25% (1/4) chance of having a child with type O
blood, you should know that their chances of having two children with type O blood
is 1/4 x 1/4 = 1/16.
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HUMAN GENETICS
Exam 1 Study Guide
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Explain why we use pedigrees.
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Explain what is meant when we call someone a carrier for a genetic condition.
Be able to draw out a simple pedigree to show basic family relationships. (In terms of
the different pedigree symbols, just know how to depict males and females, both
affected and normal. The more fancy symbols are not important.)
Be able to identify the following patterns of inheritance on a pedigree:
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autosomal recessive
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autosomal dominant
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mitochondrial inheritance
Week 4: Cytogenetics
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Be able to define cytogenetics and give examples of discoveries that have been made
by this field.
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Describe the technique of karyotyping and how cells are collected for this procedure.
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Explain why we might perform a karyotype.
Be able to describe and sketch an example of each of the three classes of chromosome
structure (metacentric, submetacentric, and acrocentric).
Know what the normal diploid number is in humans (this should be easy!).
Explain the difference between polyploidy and aneuploidy.
For each of the following conditions, (1) indicate whether an individual can survive to
adulthood and (2) give an example of a disease/syndrome caused by such a condition:
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Aneuploidy of an autosome
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Aneuploidy of a sex chromosome
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Identify the major risk factor for aneuploidies in humans.
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Be able to distinguish between a genetic disorder and an inherited disorder.
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Be able to identify the types of people for whom genetic counseling is recommended.
Describe some of the characteristics of a person with Down syndrome (trisomy 21),
and describe the two ways that someone can get Down syndrome.
Explain who genetic counselors are, what type of information they can provide to
patients, and what field(s) their training is in.
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2.
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BN, Bn, bN, and bn
T and t
HiJK and HiJk
EM
PM and pM
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